The ESSO KTT project for the Marlin B offshore platform consisted in part of the construction of eight insert piles comprising the installation of CHS primary steel piles that will be fully grouted with cement slurry to form an integral caisson. Concrete Spacer Blocks consisting 1914mm diameter cylinders with 600mm inner diameter central hole and 5180mm high were installed in the piles to decrease the quantity of grouting. There are to be 13 blocks placed in each pile.
The ‘Spacer Blocks’ will be Pre-Cast and cured by GBG Concrete Pty Ltd at their facility in Sale, then transported by road to the marine terminal for shipment offshore via transport vessel. Once offshore, the blocks will be individually lifted and stacked inside the platforms tubular foundation piles and then grouted in place.
ESSO engaged Airey Taylor Consultants (ATC) to prepare a concept design report. As part of their contract, GBG Concrete were requested to re-verify the design of the Concrete Spacer Blocks, and GBG engaged GHD to undertake this work.
In 2010, Dr James Aldred, as Principal Consultant with GHD, was involved with the review of the concrete mix design, concrete materials, thermal monitoring and insulation as well as strength development. James also witnessed and monitored the casting of a full size prototype concrete spacer block.